diff --git a/doc/man-sections/server-options.rst b/doc/man-sections/server-options.rst index 047f2270f..1ab00e81b 100644 --- a/doc/man-sections/server-options.rst +++ b/doc/man-sections/server-options.rst @@ -35,7 +35,7 @@ fast hardware. SSL/TLS authentication must be used in this mode. token is reached or after not being renewed for more than 2 \* ``reneg-sec`` seconds. Clients will be sent renewed tokens on every TLS renogiation to keep the client's token updated. This is done to - invalidate a token if a client is disconnected for a sufficently long + invalidate a token if a client is disconnected for a sufficiently long time, while at the same time permitting much longer token lifetimes for active clients. @@ -46,7 +46,7 @@ fast hardware. SSL/TLS authentication must be used in this mode. When the :code:`external-auth` keyword is present the normal authentication method will always be called even if auth-token succeeds. Normally other authentications method are skipped if auth-token - verification suceeds or fails. + verification succeeds or fails. This option postpones this decision to the external authentication methods and checks the validity of the account and do other checks. diff --git a/src/openvpn/auth_token.c b/src/openvpn/auth_token.c index 0ea6d1832..a681d726f 100644 --- a/src/openvpn/auth_token.c +++ b/src/openvpn/auth_token.c @@ -109,11 +109,11 @@ add_session_token_env(struct tls_session *session, struct tls_multi *multi, /* * No session before, generate a new session token for the new session */ - if (!multi->auth_token) + if (!multi->auth_token_initial) { generate_auth_token(up, multi); } - session_id_source = multi->auth_token; + session_id_source = multi->auth_token_initial; } /* * In the auth-token the auth token is already base64 encoded @@ -184,7 +184,7 @@ generate_auth_token(const struct user_pass *up, struct tls_multi *multi) uint8_t sessid[AUTH_TOKEN_SESSION_ID_LEN]; - if (multi->auth_token) + if (multi->auth_token_initial) { /* Just enough space to fit 8 bytes+ 1 extra to decode a non padded * base64 string (multiple of 3 bytes). 9 bytes => 12 bytes base64 @@ -192,11 +192,14 @@ generate_auth_token(const struct user_pass *up, struct tls_multi *multi) */ char old_tstamp_decode[9]; + /* Make a copy of the string to not modify multi->auth_token_initial */ + char* initial_token_copy = string_alloc(multi->auth_token_initial, &gc); + /* * reuse the same session id and timestamp and null terminate it at * for base64 decode it only decodes the session id part of it */ - char *old_sessid = multi->auth_token + strlen(SESSION_ID_PREFIX); + char *old_sessid = initial_token_copy + strlen(SESSION_ID_PREFIX); char *old_tsamp_initial = old_sessid + AUTH_TOKEN_SESSION_ID_LEN*8/6; old_tsamp_initial[12] = '\0'; @@ -212,10 +215,6 @@ generate_auth_token(const struct user_pass *up, struct tls_multi *multi) old_tsamp_initial[0] = '\0'; ASSERT(openvpn_base64_decode(old_sessid, sessid, AUTH_TOKEN_SESSION_ID_LEN)==AUTH_TOKEN_SESSION_ID_LEN); - - - /* free the auth-token, we will replace it with a new one */ - free(multi->auth_token); } else if (!rand_bytes(sessid, AUTH_TOKEN_SESSION_ID_LEN)) { @@ -272,11 +271,22 @@ generate_auth_token(const struct user_pass *up, struct tls_multi *multi) free(b64output); + /* free the auth-token if defined, we will replace it with a new one */ + free(multi->auth_token); multi->auth_token = strdup((char *)BPTR(&session_token)); dmsg(D_SHOW_KEYS, "Generated token for client: %s (%s)", multi->auth_token, up->username); + if (!multi->auth_token_initial) + { + /* + * Save the initial auth token to continue using the same session ID + * and timestamp in updates + */ + multi->auth_token_initial = strdup(multi->auth_token); + } + gc_free(&gc); } @@ -353,13 +363,7 @@ verify_auth_token(struct user_pass *up, struct tls_multi *multi, bool in_renog_time = now >= timestamp && now < timestamp + 2 * session->opt->renegotiate_seconds; - /* We could still have a client that does not update - * its auth-token, so also allow the initial auth-token */ - bool initialtoken = multi->auth_token_initial - && memcmp_constant_time(up->password, multi->auth_token_initial, - strlen(multi->auth_token_initial)) == 0; - - if (!in_renog_time && !initialtoken) + if (!in_renog_time) { ret |= AUTH_TOKEN_EXPIRED; } diff --git a/src/openvpn/push.c b/src/openvpn/push.c index f4957f147..53cb7ca6f 100644 --- a/src/openvpn/push.c +++ b/src/openvpn/push.c @@ -527,14 +527,6 @@ prepare_auth_token_push_reply(struct tls_multi *tls_multi, struct gc_arena *gc, push_option_fmt(gc, push_list, M_USAGE, "auth-token %s", tls_multi->auth_token); - if (!tls_multi->auth_token_initial) - { - /* - * Save the initial auth token for clients that ignore - * the updates to the token - */ - tls_multi->auth_token_initial = strdup(tls_multi->auth_token); - } } } diff --git a/src/openvpn/ssl_common.h b/src/openvpn/ssl_common.h index 43d6276be..1914a0015 100644 --- a/src/openvpn/ssl_common.h +++ b/src/openvpn/ssl_common.h @@ -597,8 +597,8 @@ struct tls_multi * user/pass authentications in this session. */ char *auth_token_initial; - /**< The first auth-token we sent to a client, for clients that do - * not update their auth-token (older OpenVPN3 core versions) + /**< The first auth-token we sent to a client. We use this to remember + * the session ID and initial timestamp when generating new auth-token. */ #define AUTH_TOKEN_HMAC_OK (1<<0) /**< Auth-token sent from client has valid hmac */ diff --git a/src/openvpn/ssl_verify.c b/src/openvpn/ssl_verify.c index bbb1878a3..61dde1791 100644 --- a/src/openvpn/ssl_verify.c +++ b/src/openvpn/ssl_verify.c @@ -1639,7 +1639,9 @@ verify_user_pass(struct user_pass *up, struct tls_multi *multi, * Otherwise the auth-token get pushed out as part of the "normal" * push-reply */ - if (multi->auth_token_initial) + bool is_renegotiation = session->key[KS_PRIMARY].key_id != 0; + + if (multi->auth_token_initial && !is_renegotiation) { /* * We do not explicitly schedule the sending of the @@ -1648,7 +1650,7 @@ verify_user_pass(struct user_pass *up, struct tls_multi *multi, * established and furthermore since this is called in * the middle of authentication, there are other messages * (new data channel keys) that are sent anyway and will - * trigger schedueling + * trigger scheduling */ send_push_reply_auth_token(multi); } diff --git a/tests/unit_tests/openvpn/test_auth_token.c b/tests/unit_tests/openvpn/test_auth_token.c index 4030052e0..a504eed91 100644 --- a/tests/unit_tests/openvpn/test_auth_token.c +++ b/tests/unit_tests/openvpn/test_auth_token.c @@ -174,7 +174,10 @@ auth_token_test_timeout(void **state) now = 100000; generate_auth_token(&ctx->up, &ctx->multi); + strcpy(ctx->up.password, ctx->multi.auth_token); + free(ctx->multi.auth_token_initial); + ctx->multi.auth_token_initial = NULL; /* No time has passed */ assert_int_equal(verify_auth_token(&ctx->up, &ctx->multi, ctx->session), @@ -244,10 +247,10 @@ auth_token_test_known_keys(void **state) now = 0; /* Preload the session id so the same session id is used here */ - ctx->multi.auth_token = strdup(now0key0); + ctx->multi.auth_token_initial = strdup(now0key0); /* Zero the hmac part to ensure we have a newly generated token */ - zerohmac(ctx->multi.auth_token); + zerohmac(ctx->multi.auth_token_initial); generate_auth_token(&ctx->up, &ctx->multi);